package com.hmdp.utils;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {
    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    private static final long BEGIN_TIMESTAMP = 1640995200L;
    private static final int COUNT_BITS = 32;

    public long nextId(String keyPrefix){
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowEpochSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowEpochSecond - BEGIN_TIMESTAMP;
        //2.生成序列号
        String date = now.format(DateTimeFormatter.ofPattern("yyyyMMdd")); //精确到天，一天一个key
        Long count = stringRedisTemplate.opsForValue().increment("increment:" + keyPrefix + ":" + date);
        //3.拼接
        return timestamp << COUNT_BITS | count;
    }
}

